Folded parallel-light-channel based stereo imaging system with disparity and convergence angle control

ABSTRACT

A stereo imaging system having convergence angle and disparity control includes a pair of pivoting folded-parallel-light-channel (FPLC) units arranged to provide a virtual left side view and a virtual right side view of a scene. Each FPLC unit includes a fixed lens unit adapted to focus reflected light comprising an image of a scene to an image sensor and a laterally translatable light-redirecting unit comprising a reflector adapted to define a parallel image reflection path to the fixed lens unit via a collimated light beam comprising substantially parallel light beams. The stereo imaging system further includes a disparity-adjusting mechanism adapted to alter a distance between the pair of pivoting FPLC units and a convergence-angle-adjusting mechanism adapted to pivot the pivoting FPLC units.

This utility patent application claims the benefit of priority in U.S.Provisional Patent Application Ser. No. 62/407,754 filed on Oct. 13,2016, the entirety of the disclosure of which is incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates to stereo imaging. More specifically,this disclosure pertains to a compact folded-parallel-light-channel(FPLC) stereo imaging system synchronously generating a left view and aright view of a scene, and also providing both disparity and convergenceangle control. The disclosed stereo imaging system finds utility in avariety of devices including compact mobile devices such as cell phonesand smartphones.

BACKGROUND OF THE INVENTION

A critical point in designing an embedded imaging system for a handheldor other mobile device such as a smartphone is to ensure the height(thickness) of the imaging system is smaller than (or, at least, closeto) the thickness of the cell phone. The image sensor of a cell phoneimaging system is of a fixed dimension (4.80×3.60 mm). To ensure imagesof the same size as the image sensor are produced, one cannotunlimitedly reduce the sizes of the lenses used in a cell phone imagingsystem. Hence, a telephoto camera usually cannot be used for a mobiledevice such as a smartphone since such a camera when equipped withcamera comprising a plurality of lenses disposed to refract light toform an image at a cell phone camera image sensor (CPCIS), would requireat least 14 mm for its height (see FIG. 1 for an example) while thethickness of a typical smartphone is between 7 and 9 mm only.

To allow a telephoto camera equipped with a CPCIS to be embedded in asmartphone, prior art devices are known (see FIG. 2) wherein thetelephoto camera is “folded” by inserting a light-folding mirror in thelens system so that the optical axis (see dotted line) is redirectedfrom vertical to horizontal once it reaches the folding mirror. Theimage sensor is installed on an orientation defining a plane orientedvertically to a plane defined by the ground, instead of parallel to aplane defined by the ground. By folding a telephoto camera equipped witha CPCIS in this manner, the height of the camera can be made as small as7 mm and consequently can be embedded into a smart cell phone. Asexamples, see U.S. Pat. No. 9,316,810 to Mercado and U.S. Pat. No.9,172,856 to Bohn et al., the entire disclosures of each of which areincorporated herein by reference.

In theory, a stereo imaging system could be provided by arranging twoidentical imaging systems such as those shown in FIG. 2 symmetrically asshown in FIG. 3. Such a hypothetical stereo imaging system could beembedded in a mobile device such as a smartphone completely. However,the only way to provide disparity (interocular distance) control forsuch a stereo imaging system would be to configure each of the left andright imaging systems to translate laterally in their entirety relativeto one another. This is illustrated in FIG. 3. Such an arrangement,while hypothetically configurable, would require additional packagingspace potentially not available in small mobile devices such assmartphones.

Accordingly, a need in the art is identified for improvements to imagingsystems for small mobile devices, providing stereo imaging systemsincluding such convergence and disparity control. The followingdisclosure describes a folded-parallel-light-channel stereo imagingsystem for a mobile device configured to allow disparity and convergenceangle control without requiring motion of each entire unit relative toone another.

SUMMARY OF THE INVENTION

To solve the foregoing problems and address the identified need in theart, in one aspect of the present disclosure a stereo imaging systemhaving convergence angle and disparity control is provided, comprising apair of pivoting folded-parallel-light-channel (FPLC) units arranged toprovide a virtual left side view and a virtual right side view of ascene. Each FPLC unit comprises a fixed lens unit adapted to focusreflected light comprising an image of a scene to an image sensor, and alaterally translatable light-redirecting unit comprising a reflectoradapted to define a parallel image reflection path to the fixed lensunit via a collimated light beam comprising substantially parallel lightbeams. The stereo imaging system further includes a disparity-adjustingmechanism adapted to alter a distance between the pair of pivoting FPLCunits and a convergence-angle-adjusting mechanism adapted to pivot thepivoting FPLC units.

In embodiments, the disparity-adjusting mechanism comprises a firstactuator operatively connected to a cam assembly. In embodiments, theconvergence-angle-adjusting mechanism comprises a second actuatoradapted to pivot a pair of pivoting housings each respectively carryinga one of the pair of FPLC units.

In embodiments, the reflector defines a planar reflective surface. Aconcave lens may be disposed between the reflector and an image inlet ofeach of the pair of FPLC units. This concave lens defines a lens fieldof view that is the same as a field of view of the fixed lens unit. Inalternative embodiments, the reflector defines an arcuate reflectivesurface. The arcuate reflective surface may be configured to define areflector field of view that is the same as a field of view of the fixedlens unit. In embodiments, the fixed lens unit defines a wide-angle lensunit. In alternative embodiments, the fixed lens unit defines atelephoto lens unit.

In another aspect, a stereo imaging system having convergence angle anddisparity control is provided, comprising a pair of pivotingfolded-parallel-light-channel (FPLC) units arranged to provide a virtualleft side view and a virtual right side view of a scene. Each FPLC unitcomprises a fixed lens unit adapted to focus reflected light comprisingan image of a scene to an image sensor and a laterally translatablelight-redirecting unit comprising a planar reflector adapted to define aparallel image reflection path to the fixed lens unit via a collimatedlight beam comprising substantially parallel light beams. The disclosedsystem further includes a disparity-adjusting mechanism adapted to altera distance between the pair of pivoting FPLC units and aconvergence-angle-adjusting mechanism adapted to pivot the pivoting FPLCunits. The disparity-adjusting mechanism and theconvergence-angle-adjusting mechanism may be as described above.

In yet another aspect, a stereo imaging system having convergence angleand disparity control is provided, comprising a pair of pivotingfolded-parallel-light-channel (FPLC) units arranged to provide a virtualleft side view and a virtual right side view of a scene. Each FPLC unitcomprises a fixed lens unit adapted to focus reflected light comprisingan image of a scene to an image sensor and a laterally translatablelight-redirecting unit comprising an arcuate reflector adapted to definea parallel image reflection path to the fixed lens unit via a collimatedlight beam comprising substantially parallel light beams. The disclosedsystem further includes a disparity-adjusting mechanism adapted to altera distance between the pair of pivoting FPLC units and aconvergence-angle-adjusting mechanism adapted to pivot the pivoting FPLCunits. The disparity-adjusting mechanism and theconvergence-angle-adjusting mechanism may be as described above.

These and other embodiments, aspects, advantages, and features of thepresent invention will be set forth in the description which follows,and in part will become apparent to those of ordinary skill in the artby reference to the following description of the invention andreferenced drawings or by practice of the invention. The aspects,advantages, and features of the invention are realized and attained bymeans of the instrumentalities, procedures, and combinationsparticularly pointed out in the appended claims. Unless otherwiseindicated, any patent and/or non-patent citations discussed herein arespecifically incorporated by reference in their entirety into thepresent disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a prior art imager for a mobile device such as acellphone or smartphone;

FIG. 2 depicts a prior art folded light-path imager for a mobile devicesuch as a cellphone or smartphone;

FIG. 3 illustrates a hypothetical stereo imager derived from the imagerof FIG. 2;

FIG. 4 schematically illustrates a stereo imaging system according tothe present disclosure;

FIG. 5 shows in isolation a folded-parallel-light-channel-based cameraunit for use in the stereo imaging system of FIG. 4;

FIG. 6 shows operation of a convergence angle adjusting mechanism forthe stereo imaging system of FIG. 4;

FIG. 7 shows in isolation a folded-parallel-light-channel-based cameraunit for use in the stereo imaging system of FIG. 4, comprising afolding unit having a curved reflective surface and a multiple-lensblock unit comprising three lenses;

FIG. 8 shows a curved reflector for use in the camera unit of FIG. 7;

FIG. 9 shows in isolation a folded-parallel-light-channel-based cameraunit for use in the stereo imaging system of FIG. 4, comprising afolding unit having a curved reflective surface and a multiple-lensblock unit comprising five lenses;

FIG. 10 shows in isolation a folded-parallel-light-channel-based cameraunit for use in the stereo imaging system of FIG. 4, comprising afolding unit having a planar reflective surface and a multiple-lensblock unit comprising three lenses;

FIG. 11 shows in isolation a folded-parallel-light-channel-based cameraunit for use in the stereo imaging system of FIG. 4, comprising afolding unit having a planar reflective surface and a multiple-lensblock unit comprising five lenses; and

FIG. 12 illustrates a disparity adjusting mechanism for the stereoimaging system of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the illustrated embodiments,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, specific embodiments inwhich the invention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention. Also, it is to be understood that other embodiments may beutilized and that process, reagent, materials, software, and/or otherchanges may be made without departing from the scope of the presentinvention.

The present disclosure is directed to a stereo imaging system 100 for amobile device that not only has a lesser thickness dimension, but isalso provided with the capacity of disparity and convergence anglecontrol. With reference to FIGS. 4 and 5, the stereo imaging system 100includes two substantially identical FPLC based camera units 102 a, 102b disposed symmetrically to synchronously generate a left view and aright view of a scene viewed by the stereo imaging system. EachFPLC-based camera unit 102 a, 102 b is contained in a separate pivotablehousing 103 a, 103 b. The FPLC-based camera units 102 a, 102 b eachinclude a light-folding unit 104 a, 104 b to fold a light path (seedotted lines) entering the FPLC-based camera, and a multiple-lens blockunit 106 a, 106 b to form images. Light rays entering the light-foldingunit 104 a, 104 b of the FPLC-based camera 102 a, 102 b on a first lightpath are redirected by a folding element 108 a, 108 b (not shown in thisview) on to a second light path as a collimated light beam comprisingparallelly-oriented light rays (see solid lines). The folding element108 a, 108 b may include a flat reflective surface or a curvedreflective surface. The parallelly-oriented light rays of the collimatedlight beam are then refracted by lenses (not shown in this view) of themultiple-lens block unit 106 a, 106 b in the second light path to forman image at an image sensor 110 a, 110 b. As will be described, eachFPLC based camera 102 a, 102 b may be configured to provide a telephotolens system embodiment or a wide-angle lens system embodiment. Eachembodiment satisfies the requirement of parallelly-oriented light raytransmission between the light-folding unit 104 a, 104 b and themultiple-lens block unit 106 a, 106 b.

As shown representatively in FIG. 5, each FPLC-based camera unit 102 a,102 b by its configuration respectively defines a virtual camera 112 a,112 b (only virtual camera 112 a is shown in the drawing figure) whichrepresents, respectively, a left or a right view of the scene astransmitted to each image sensor 110 a, 110 b.

In either embodiment, disparity of the left view and the right view ofthe stereo imaging system 100 can be adjusted by adjusting a distancebetween the light-folding units 104 a, 104 b of the two FPLC basedcamera units 102 a, 102 b. Likewise, a convergence angle of the leftview and the right view of the stereo imaging system 100 can be adjustedby adjusting an angle between the left FPLC based camera unit 102 a andthe right FPLC based camera unit 102 b. Mechanisms for effecting theseadjustments will be described below.

FIGS. 7, 8, and 9 illustrate implementation of FPLC-based camera units102 a, 102 b comprising folding element 108 a, 108 b having curvedreflective surfaces. In the embodiment depicted in FIG. 7, themultiple-lens block unit 106 a comprises three lenses 114 a, 114 b, 114c. In the embodiment depicted in FIG. 9, the multiple-lens block unit106 a comprises five lenses 114 a, 114 b, 114 c, 114 d, and 114 e. Aswill be appreciated, the curved folding elements 108 a, 108 b areprovided having a curvature whereby a field of view of the curvedfolding elements 108 a, 108 b is the same as that of a field of view ofthe multiple-lens block units 106 a, 106 b. In this embodiment, thefield of view of the curved folding elements 108 a, 108 b defines thefield of view of the FPLC-based camera units 102 a, 102 b.

FIGS. 10 and 11 illustrate implementation of FPLC-based camera units 102a, 102 b comprising folding elements 108 a, 108 b having planarreflective surfaces. FIG. 10 shows an FPLC-based camera unit 102 ahaving a multiple-lens block unit 106 a comprising three lenses 114 a,114 b, 114 c, whereas FIG. 11 shows an FPLC-based camera unit 102 ahaving a multiple-lens block unit 106 a comprising five lenses 114 a,114 b, 114 c, 114 d, and 114 e. In these embodiments, concave lenses 116a, 116 b (only lens 116 a shown in the drawings) are provided as part ofthe light-folding units 104 a, 104 b, disposed in the light pathentering the FPLC-based camera units. As will be appreciated, theconcave lenses 116 a, 116 b are provided having a curvature whereby afield of view of the concave lenses 116 a, 116 b is the same as that ofa field of view of the multiple-lens block units 106 a, 106 b. In thisembodiment, the field of view of the concave lenses 116 a, 116 b definesthe field of view of the FPLC-based camera units 102 a, 102 b.

As will be appreciated, by ensuring that the field of view of the lightfolding units 104 a, 104 b is the same as that of the multiple-lensblock units 106 a, 106 b as described above, the multiple-lens blockunits 106 a, 106 b are able to provide an image of a scene that is thesame size as that of the image sensors 110 a, 110 b. Further, because ofthe parallel path of travel of light rays from the light-foldingelements 108 a, 108 b to the multiple-lens block units 106 a, 106 b, thefields of view of the light folding units 104 a, 104 b are independentof the spacing or distance of the light folding units from the multiplelens block units 106 a, 106 b. By this feature, adjustment of disparitywithout requiring movement of the multiple-lens block units 106 a, 106 band/or the image sensors 110 a, 110 b is made possible by the mechanismsdescribed below.

FIGS. 7 and 10 illustrate wide-angle multiple lens block units 106 a,106 b paired respectively with curved and planar light-folding units 104a, 104 b. In turn, FIGS. 9 and 11 illustrate telephoto multiple-lensblock units 106 a, 106 b paired respectively with curved and planarlight-folding units 104 a, 104 b. In each case, the field of view of thelight-folding units 104 a, 104 b is the same as that of the field ofview of the multiple-lens block units 106 a, 106 b. It will beappreciated, however, that the described stereo imaging system 100 isnot limited to wide-angle and telephoto lens systems, but instead may beconfigured with any suitable lens system wherein the light-folding units104 a, 104 b can be configured with a same field of view as themultiple-lens block units 106 a, 106 b such that the multiple-lens blockunits can produce an image of a scene that is the same size as the imagesensors 110 a, 110 b comprised in the stereo imaging system.

As described above in the discussion of FIGS. 4 and 5, the light-foldingunits 104 a, 104 b define virtual cameras 112 a, 112 b, describedrespectively in reference to an orientation of the stereo imaging system100 as the left and right virtual camera 112 a, 112 b. The distance D(see FIG. 4 and FIG. 6) between the left and right virtual camera 112 a,112 b is variously called the interocular distance, virtual cameradistance, virtual camera disparity, or simply disparity. It is thisdistance D that determines the disparity between a left view and a rightview of a scene. In turn, each virtual camera 112 a, 112 b has a line ofsight, referred to as the optical axis O (see FIGS. 5, 7, and 9-11). Theangle between the optical axes of the virtual cameras 112 a, 112 b iscalled the convergence angle A (see FIG. 6). Advantageously, thedescribed stereo imaging system 100 of the present disclosure providesfor adjustment of both the interocular distance/disparity andconvergence angle.

With regard to adjustment of convergence angle, referring back to FIG. 4and to FIG. 6, each FPLC-based camera unit 102 a, 102 b housing 103 a,103 b is pivotally (see FIG. 6, arrows B) attached to a stereo imagingsystem housing 118. In the depicted embodiment, the FPLC-based cameraunits 102 a, 102 b are respectively pivotally attached to the stereoimaging system housing 118 by a rotating shaft 120 a, 120 b. Aconvergence-angle-adjusting mechanism 122 is provided, in the depictedembodiment comprising a biasing actuator 124 and at least two biasingmembers 126. Rotating the biasing actuator 124 in a first direction willurge each camera unit housing 103 a, 103 b to rotate about an axisdefined by the rotating shafts 120 a, 120 b, thus altering an anglebetween the FPLC-based camera unit 102 a, 102 b optical axes O and soaltering a convergence angle of the stereo imaging system 100. Rotatingthe biasing actuator 124 in a second, opposed direction will return thecamera unit housings to their original orientations, assisted by thebiasing actions of the biasing members 126. In turn, the biasing actionof the biasing members 126 ensures stability of the adjusting process.

With reference to FIGS. 4 and 12, a disparity adjusting mechanism 128 isalso provided. In the depicting embodiment, the disparity adjustingmechanism 128 comprises an arrangement of guide rods 130 to which eachlight folding unit 104 a, 104 b is slidingly attached. A cam array 132is provided, disposed between each light folding unit 104 a, 104 b andunder control of a disparity adjusting actuator 134. In the depictedembodiment, the cam array 132 comprises a pair of elliptical cams 136 a,136 b disposed whereby actuating the disparity adjusting actuator 134causes the cams 136 a, 136 b to rotate in opposed directions (seearrows). As will be appreciated, this will bias the light folding units104 a, 104 b, translating them laterally to increase a distancetherebetween. In turn, a plurality of biasing members 138, in thedepicted embodiment being springs concentrically around each guide rod130, are disposed to bias the light folding units 104 a, 104 b towardsone another in an opposite direction to the biasing force imposed by thecam array 132. Thus, by this disparity adjusting mechanism 128 the lightfolding units 104 a, 104 b may be translated laterally to alter adistance therebetween, and by this mechanism disparity can be controlledfor the stereo imaging system 100. Likewise, the biasing members 138provide stability to the disparity adjusting process.

Summarizing, the present disclosure provides a stereo imaging system 100wherein a width/height dimension of the system is minimized, and so thedescribed stereo imaging system is readily adapted to small mobiledevices such as smartphones. In turn, because the described lightfolding units 104 a, 104 b reflect light/images to the multiple lensblock units 106 a, 106 b as a collimated light beam comprising parallellight rays, the field of view of the light folding units 104 a, 104 b isindependent of any distance between the light folding units and themultiple-lens block units. Thus, disparity control is possible for thestereo imaging system 100 without requiring movement of the multiplelens block units 106 a, 106 b and/or the image sensors 110 a, 110 b.This further contributes to the compact design of the described stereoimaging system 100. Still more, by the described mechanisms convergenceangle control is made possible, i.e., adjusting an angle between opticalaxes of the virtual cameras 112 a, 112 b defined by the system. Theimages captured by image sensors 110 a, 110 b representing respectivelya left and a right view of a scene can then be processed to providestereoscopic images and/or image-plus-depth images, i.e.three-dimensional images. Likewise, use of the described system toprovide still images and video images in stereo and/or image-plus-depthis contemplated. A number of suitable methods, systems, and computerprogram products for processing images to provide stereoscopic and/orimage-plus-depth images are known and contemplated for use herein,including without intending any limitation the methods described in U.S.Pat. Nos. 8,648,808, 8,964,004, 9,201,519, and 9,310,857, thedisclosures of which are incorporated herein by reference in theirentirety. In turn, the described system is readily adaptable of othercamera types, including without intending any limitation compactdual-lens reflex cameras.

One of ordinary skill in the art will recognize that additionalembodiments of the invention are also possible without departing fromthe teachings herein. Thus, the foregoing description is presented forpurposes of illustration and description of the various aspects of theinvention, and one of ordinary skill in the art will recognize thatadditional embodiments of the invention are possible without departingfrom the teachings herein. This detailed description, and particularlythe specific details of the exemplary embodiments, is given primarilyfor clarity of understanding, and no unnecessary limitations are to beimported, for modifications will become obvious to those skilled in theart upon reading this disclosure and may be made without departing fromthe spirit or scope of the invention. Relatively apparent modifications,of course, include combining the various features of one or more figureswith the features of one or more of other figures. All suchmodifications and variations are within the scope of the invention asdetermined by the appended claims when interpreted in accordance withthe breadth to which they are fairly, legally and equitably entitled.

What is claimed is:
 1. A stereo imaging system having convergence angleand disparity control, comprising: a pair of pivotingfolded-parallel-light-channel (FPLC) units arranged to provide a virtualleft side view and a virtual right side view of a scene, each FPLC unitcomprising: a) a fixed lens unit adapted to focus reflected lightcomprising an image of a scene to an image sensor, and b) a laterallytranslatable light-redirecting unit comprising a reflector adapted todefine a parallel image reflection path to the fixed lens unit via acollimated light beam comprising substantially parallel light beams; adisparity-adjusting mechanism adapted to alter a distance between thelaterally translatable light-redirecting units of the pair of pivotingFPLC units; and a convergence-angle-adjusting mechanism adapted to pivotthe pivoting FPLC units.
 2. The stereo imaging system according to claim1, wherein the disparity-adjusting mechanism comprises a first actuatoroperatively connected to a cam assembly.
 3. The stereo imaging systemaccording to claim 2, wherein the convergence-angle-adjusting mechanismcomprises a second actuator adapted to pivot a pair of pivoting housingseach respectively carrying a one of the pair of FPLC units.
 4. Thestereo imaging system according to claim 1, wherein the reflectordefines a planar reflective surface.
 5. The stereo imaging systemaccording to claim 4, further including a concave lens disposed betweenthe reflector and an image inlet of each of the pair of FPLC units. 6.The stereo imaging system according to claim 5, wherein the concave lensdefines a lens field of view that is the same as a field of view of thefixed lens unit.
 7. The stereo imaging system according to claim 1,wherein the reflector defines an arcuate reflective surface.
 8. Thestereo imaging system according to claim 7, wherein the arcuatereflective surface is configured to define a reflector field of viewthat is the same as a field of view of the fixed lens unit.
 9. Thestereo imaging system according to claim 1, wherein the fixed lens unitdefines a wide-angle lens unit.
 10. The stereo imaging system accordingto claim 1, wherein the fixed lens unit defines a telephoto lens unit.11. A stereo imaging system having convergence angle and disparitycontrol, comprising: a pair of pivoting folded-parallel-light-channel(FPLC) units arranged to provide a virtual left side view and a virtualright side view of a scene, each FPLC unit comprising: a) a fixed lensunit adapted to focus reflected light comprising an image of a scene toan image sensor, and b) a laterally translatable light-redirecting unitcomprising a planar reflector adapted to define a parallel imagereflection path to the fixed lens unit via a collimated light beamcomprising substantially parallel light beams; a disparity-adjustingmechanism adapted to alter a distance between the laterally translatablelight-redirecting units of the pair of pivoting FPLC units; and aconvergence-angle-adjusting mechanism adapted to pivot the pivoting FPLCunits.
 12. The stereo imaging system according to claim 11, wherein thedisparity-adjusting mechanism comprises a first actuator operativelyconnected to a cam assembly.
 13. The stereo imaging system according toclaim 12, wherein the convergence-angle-adjusting mechanism comprises asecond actuator adapted to pivot a pair of pivoting housings eachrespectively carrying a one of the pair of FPLC units.
 14. The stereoimaging system according to claim 11, further including a concave lensdisposed between the planar reflector and an image inlet of each of thepair of FPLC units.
 15. The stereo imaging system according to claim 14,wherein the concave lens defines a lens field of view that is the sameas a field of view of the fixed lens unit.
 16. The stereo imaging systemaccording to claim 11, wherein the fixed lens unit defines a wide-anglelens unit.
 17. The stereo imaging system according to claim 11, whereinthe fixed lens unit defines a telephoto lens unit.
 18. A stereo imagingsystem having convergence angle and disparity control, comprising: apair of pivoting folded-parallel-light-channel (FPLC) units arranged toprovide a virtual left side view and a virtual right side view of ascene, each FPLC unit comprising: a) a fixed lens unit adapted to focusreflected light comprising an image of a scene to an image sensor, andb) a laterally translatable light-redirecting unit comprising an arcuatereflector adapted to define a parallel image reflection path to thefixed lens unit via a collimated light beam comprising substantiallyparallel light beams; a disparity-adjusting mechanism adapted to alter adistance between the laterally translatable light-redirecting units ofthe pair of pivoting FPLC units; and a convergence-angle-adjustingmechanism adapted to pivot the pivoting FPLC units.
 19. The stereoimaging system according to claim 18, wherein the disparity-adjustingmechanism comprises a first actuator operatively connected to a camassembly.
 20. The stereo imaging system according to claim 19, whereinthe convergence-angle-adjusting mechanism comprises a second actuatoradapted to pivot a pair of pivoting housings each respectively carryinga one of the pair of FPLC units.
 21. The stereo imaging system accordingto claim 18, wherein the arcuate reflective surface is configured todefine a reflector field of view that is the same as a field of view ofthe fixed lens unit.
 22. The stereo imaging system according to claim18, wherein the fixed lens unit defines a wide-angle lens unit.
 23. Thestereo imaging system according to claim 18, wherein the fixed lens unitdefines a telephoto lens unit.